1. Field of the Invention
The present invention relates to an image pickup apparatus having a plurality of white balance modes, and a white balance control method thereof, and a storage medium.
2. Description of the Related Art
Digital cameras are conventionally known which is capable of outputting a video signal of the digital camera as it is (see Japanese Laid-Open Patent Publication (Kokai) No. 11-261933 and Japanese Laid-Open Patent Publication (Kokai) No. 2001-223979). Utilizing image data of a video signal as it is (hereunder, referred to as “the raw data”) is utilized enables image correction processing to be expected after photographing.
Since the raw data is image data of a video signal as it is, the raw data can be converted into commonly handled image data such as JPEG format data by performing image processing (hereunder, referred to as “the development”) on the raw data. A function of adjusting the white balance is one kind of image correction processing for the raw data. With this function, it is possible to switch a white balance mode after photographing to obtain image data having the appropriate color tones.
Technology is also known of improving the accuracy of white balance adjustment when a white balance mode is switched by storing information that shows a shift in a blackbody locus in the raw data (see Japanese Laid-Open Patent Publication (Kokai) No. 2003-324746).
However, there is the following problem with the conventional image pickup apparatus described above. That is, when setting a white balance (WB) mode to perform correction processing for color tones, it is necessary to perform integration processing for video signals included in the raw data and also perform WB calculation processing utilizing an integration value that is obtained by the integration processing.
Conventionally, when performing this processing and switching among a plurality of white balance settings to view changes in color tones, there is a problem that it is necessary to execute the aforementioned integration processing and calculation processing for each white balance mode, to require substantial processing time.
Further, the amount of data in video signals is increasing because of the increasing numbers of pixels in images captured by image pickup devices in recent years. As a result, the processing times required for integration processing and calculation processing are steadily increasing.
Furthermore, with respect to image pickup apparatuses having a function of capturing an image as the raw data, when image data subjected to the development processing at the image pickup apparatus main unit is compared with image data obtained after subjecting the raw data to the development processing on a PC or the like after photographing, the processing and the results relating to white balance adjustment are not the same. As a result, there is a problem that the color reproduction properties deteriorate.